Rental property investment starts with finding the best deals. To do this, you can increase your odds by finding more deals. Who's more likely to get a cheap apartment building, an investor that looks through the MLS listings and calls it a day, or the one that uses ten resources? Here are those ten:
1. Look in old papers to find "For Rent" ads. Call if they are a few weeks old. The landlord may be ready to sell, especially if he hasn't yet rented the units out.

2. Look up old FSBO ads. Call on two-month-old "For sale By Owner" ads, and if they haven't sold, they may be ready to deal. Owners often give up the effort, but still would love to sell. Help them out!
3.

Drive around looking for "For Sale By Owner" signs. Owners often don't want to pay to keep the ad in the paper every week, so you won't see all properties there.
4. Find abandoned properties. That's a pretty clear sign that the owner doesn't want to deal with the property. He might sell cheap.
5. Talk. Let people know you are looking and sometimes the properties will come to you. There are a lot of owners out there who want to sell, but haven't yet listed their property.

6. Talk to bankers. You might get a foreclosed rental property cheaper if you buy it before they list it with a real estate agent.
7. Offer someone a finder's fee. There are people that always seem to hear about the good deals. Have such people coming to you.
8. Eviction notices. If your local papers publish eviction notices, or if you can get the information at the courthouse, it can be useful.

A landlord who just went through the procees of evicting tenants is a likely seller.
9. Use the internet. Go to a search engine and enter the type of real estate you are looking for, along with the city you want to invest in. You never know what you might find.
10. Put an ad in the paper. "Looking for rental properties to buy," might be sufficient to generate a few calls.
There is a lot more to learn to do it right, but finding good properties is a good place to start for rental property investment.